Blob hot under Appalachians formed when Greenland separated from North America – and he heads for New York
An abnormally hot geante drop under the mountains of the Appalachians was formed when Greenland separated from North America about 80 million years ago, suggests new research.
Scientists previously thought that this hot area, known as the northern Appalachian anomaly, was left after North America has separated from Africa 180 million years ago, but this theory does not resist a new control, according to the study, published Wednesday July 30 in the journal Geology.
“This thermal upwelling has long been a confusing characteristic of North American geology”, principal author Thomas GernonProfessor of Earth Sciences at the University of Southampton in the United Kingdom, said in a statement. “It is under a part of the continent which was tectonically silent for 180 million years, so the idea that it was only a rest of the moment when the earthly mass separated has never been completely stacked.”
Instead, the new discoveries indicate that the hot blob, which is 125 miles (200 kilometers) deep and extends to 220 miles (350 km) through New England, appeared about 80 million years ago, when what is now Greenland and Canada separated. The results suggest that such blobs are occasionally formed in continent ruptures, with possible training effects for the mountains, volcanoes and ice caps.
Gernon and his colleagues described how hot blobs are formed in a study published last year in the journal Nature. Hot blobs are created when the material of the mantle of the earth rises to fill gaps in the crust left by the rifting. This material eventually cools and becomes so dense that it flows, or “drops”, trigger In the coat, the researchers called “the waves of the mantle”.
There may be special conditions required for the coat waves to be formed, said Gernon at Live Science in an e-mail, including a steep temperature gradient where the dripping material enters the coat. This means that all continent breaks do not create coat waves, said Gernon.
In relation: North America “drips” in the mantle of the earth, discover scientists
For the new study, the researchers used direct geological observations and computer simulations to model Plates tectonics and geodynamics. They simulated the initiation of a hot blob of 1,120 miles (1,800 km) northeast of the Appalachians and found that the geological processes were pushing the abyss to the southwest at a rate of 12 miles (20 km) every million years. These results were consistent with Previous estimatesAccording to the declaration.
Team simulations have shown that hot blob can have helped up the mountains of the Appalachians When it happened, resolving the long -standing question Of why the appearances remain so high despite major erosion in the last 20 million years.
“The heat at the base of a continent can weaken and eliminate part of its dense root, which makes the continent lighter and more dynamic, like a hot air balloon which rises after dropping its ballast,” said Gernon in the declaration. “It would have made the old mountains were still built in recent million years.”
Hot blobs elsewhere could explain why the mountains with a geology similar to the Appalachians are still standing, said Gernon. These blobs could also explain the rare volcanic eruptions which Bring diamonds to the surface of the earthAccording to the declaration.
Looking at the Blob of Greenland
The study focused mainly on the anomaly of the Appalachians of the North, but the researchers also examined its “twin” – a hot drop currently seated under the North Center of Greenland. This anomaly was born in the same continental rupture event, but on the other side of the rift, according to the press release. The team noted that it creates heat currents under the Greenland ice cap which influences the way the ice moves and founds today.
“Anomalies of ancient heat continue to play a key role in the formation of the dynamics of continental glacial caps from below,” said Gernon. “Even if the surface shows little sign of tectonics in progress, deep below, the consequences of the old rifting always take place.”
The anomaly of the Appalachia of the North is still in motion, and the researchers believe that it will continue on its way to reach New York in 10 to 15 million years.
Once the hot blob has left the Appalachians, the crust of the earth will settle there again, said Gernon. “In the absence of a tectonic uprising or the coat, erosion would continue to wear the mountains, gradually lowering their altitude,” he said.
Overall, the results reveal that the ruptures of continents and other major geological events can continue to influence the planet for thousands, and even millions of years, the researchers said in the press release.
“The idea that the rifting of the continents can cause drops and cells of hot rocks in depth which distribute thousands of kilometers inside the land make us rethink what we know on the banks of the continents today and in the deep past of the earth,” said the study co-author Derek KeirAn associate professor of earth sciences at the University of Southampton and at the University of Florence in Italy, in the press release.
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